A curtain grid applied directly to a mass or roof face, rather than following a wall's linear path the way a Curtain Wall does. Where a Curtain Wall is fundamentally a wall type that happens to be paneled, a Curtain System is applied face-by-face to conceptual massing or a complex roof shape - useful for a sloped glazed atrium roof or a faceted facade that doesn't sit on a single straight or curved wall path. Both share the same underlying panel/mullion mechanics.